In recent years the use of high pressure coolants in metalworking machinery has proven to be useful in increasing production efficiency and finishes of machined parts. High pressure hydraulic fluids and high pressure fluid systems in general have relied upon the use of various valves and valving techniques for the distribution of the high pressure fluids to various components. These valves variously called distribution valves, distribution devices, rotary manifolds, and other similar nomenclature employ either elastomer seals as the primary sealing component, or metal to metal sealing elements as their primary dynamic (moving) seal element.
Coolants and most fluids used as cutting oils or lubricants for use in metalworking machines are contaminated or become contaminated with particles of varying sizes. These particulates are either airborne, inherent in the fluid, or generated by wear and corrosion in the systems, in which the fluid flows. In metalworking machines the coolant is contaminated with chips from the material being cut or ground. Most fluid systems employ filtration designed to remove particles of various sizes. No filtration is perfect and consequently particles of metals and corrosion products and other minerals are always present in any flowing medium.
In valves and distribution devices employing elastomeric seals, these particles become trapped or embedded in the elastomer seals or between the seals and the moving components in a dynamic seal, causing wear, cutting and ultimately erosion and destruction of the seal and other components in the system ultimately leading to leakage and failure of the components and possible failure of the system.
In valves and distribution devices employing metal to metal seals, the particles can become trapped in the very small clearances between the sealing surfaces. The larger particles may become trapped as the flow carries these particles over the overlapping edges of the sealing elements and as these edges close on each other, much the same as a scissor closing on an obstruction. Both of these actions will damage the sealing surfaces and again cause failure of the component. Some of the existing methods of sealing employ soft metals such as brass or other copper alloy sealing elements. These devices exhibit similar failure modes as do the elastomer sealed components.
Finally it should be noted that in most prior art distribution valves, the flow passages are reduced in diameter to accommodate the sealing elements.
Accordingly, there is a current need for a valve distribution system which is damage resistant to contaminants in the flow medium.